Stephen Hawking says black holes don't exist (well, not in the way we thought)
Quantum theory says the event horizon isn't the end, Hawking now argues.
Mon, Jan 27, 2014 at 10:38 AM
If anyone knows anything about black holes, it's physicist Stephen Hawking. Heck, one of the theoretical components of a black hole is named "Hawking radiation" after theories that the award-winning scientist first proposed back in 1974. But even though Hawking himself is responsible for much of our current understanding about black holes, a new paper he just released changes things just a bit.
Before we get to that, let's recap our current understanding of black holes. They are regions of the space-time universe, possibly caused by a collapsing star, that are so unbelievably dense that their gravity sucks in everything around them and prevents even light from escaping (hence the "black" in "black hole"). The boundary, or "point of no return," for this gravitational pull beyond which escape becomes impossible is known as the event horizon.
But now Hawking says the event horizon can't really exist. In a paper he published online last week (which has not yet been peer-reviewed, not that Hawking has all that many peers), Hawking comes up with a new term: the apparent horizon. He writes that according to the branch of physics known as quantum theory, energy — aka light — and other information are capable of escaping from a black hole.
Now Hawking doesn't go so far as to actually prove this new concept — "The correct treatment remains a mystery," he told Nature — but he argues that it solves the so-called "firewall paradox," which has plagued physicists for years. That paradox, as Hawking wrote in his paper, says black holes "are surrounded by firewalls, bolts of outgoing radiation that would destroy" any object falling into the event horizon. Hawking argues that physics are so chaotic around a black hole that it's actually impossible that the boundary of the event horizon to exist, so light trying to escape from a black hole wouldn't be sucked into it. Rather, it would be suspended.
So what does this mean? As Hawking writes in his paper, the "absence of event horizons" means that, in fact, "there are no black holes." At least not in the sense we have come to know them. They exist, but they still need to be reconsidered.
Amusingly, Hawking equates all of this with an Earth-bound phenomenon. He titled his paper "Information Preservation and Weather Forecasting for Black Holes" and wrote that the chaotic nature of the fields around a black hole "will be like weather forecasting on Earth. That is unitary, but chaotic, so there is effective information loss. One can't predict the weather more than a few days in advance."
See, even Stephen Hawking can't predict if it's going to rain on Saturday. But if he's telling us something about black holes, we may as well listen.
Related on MNN: